Installations which are fed by two supply voltages from usually two different sources are increasingly being constructed in low-voltage installations. These two different sources can be, for example, a regular power supply system and a generator supply system. In order to prevent uncontrolled feeding, different apparatuses and devices are provided which ensure that only one individual feed source is active since otherwise the low-voltage installation could suffer severe damage.
In the field of circuit breakers, rear-side locks, for example, are used for this purpose, the rear-side locks being able to prevent uncontrolled connection of a further supply voltage.
The construction of these rear-side locks is generally realized by way of a rocker, wherein there is a locking lever (interlock plunger) on each rocker side, the locking lever, by virtue of one circuit breaker being switched on, being moved into the switching mechanism of the other circuit breaker and thereby ensuring that the other circuit breaker cannot be closed. A circuit breaker can no longer be switched on owing to the locking lever being extended.